[PATCH 1/8] video: Add cursor support for DM_VIDEO consoles

[Heinrich Schuchardt]

On 1/10/22 01:56, Andre Przywara wrote:
> So far the DM_VIDEO console is completely lacking any cursor, which makes
> typing and correcting quite irritating.
> 
> Add a simple cursor display by writing a SPACE glyph in the background
> colour to the next character position on the screen. Any typed character
> will naturally overwrite it, so we need to only explicitly clear it if
> the next character will appear somewhere else (newline, backspace).

Does this work with (non-monospaced) Truetype fonts?
Moving backwards in Truetype is awkward.

Best regards

Heinrich

> 
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
>   drivers/video/console_normal.c    |  1 +
>   drivers/video/vidconsole-uclass.c | 42 +++++++++++++++++++++++++++++++
>   include/video_console.h           |  1 +
>   3 files changed, 44 insertions(+)
> 
> diff --git a/drivers/video/console_normal.c b/drivers/video/console_normal.c
> index 04f022491e5..bfd3aab8d24 100644
> --- a/drivers/video/console_normal.c
> +++ b/drivers/video/console_normal.c
> @@ -160,6 +160,7 @@ static int console_normal_probe(struct udevice *dev)
>   	vc_priv->y_charsize = VIDEO_FONT_HEIGHT;
>   	vc_priv->cols = vid_priv->xsize / VIDEO_FONT_WIDTH;
>   	vc_priv->rows = vid_priv->ysize / VIDEO_FONT_HEIGHT;
> +	vc_priv->cursor_visible = true;
>   
>   	return 0;
>   }
> diff --git a/drivers/video/vidconsole-uclass.c b/drivers/video/vidconsole-uclass.c
> index f42db40d4cd..420fd86f9ac 100644
> --- a/drivers/video/vidconsole-uclass.c
> +++ b/drivers/video/vidconsole-uclass.c
> @@ -70,6 +70,26 @@ static int vidconsole_entry_start(struct udevice *dev)
>   	return ops->entry_start(dev);
>   }
>   
> +static void draw_cursor(struct udevice *dev, bool state)
> +{
> +	struct vidconsole_priv *priv = dev_get_uclass_priv(dev);
> +	struct video_priv *vid_priv = dev_get_uclass_priv(dev->parent);
> +	u32 tmp;
> +
> +	if (!priv->cursor_visible)
> +		return;
> +
> +	if (state) {
> +		tmp = vid_priv->colour_bg;
> +		vid_priv->colour_bg = vid_priv->colour_fg;
> +	}
> +
> +	vidconsole_putc_xy(dev, priv->xcur_frac, priv->ycur, ' ');
> +
> +	if (state)
> +		vid_priv->colour_bg = tmp;
> +}
> +
>   /* Move backwards one space */
>   static int vidconsole_back(struct udevice *dev)
>   {
> @@ -77,6 +97,8 @@ static int vidconsole_back(struct udevice *dev)
>   	struct vidconsole_ops *ops = vidconsole_get_ops(dev);
>   	int ret;
>   
> +	draw_cursor(dev, false);
> +
>   	if (ops->backspace) {
>   		ret = ops->backspace(dev);
>   		if (ret != -ENOSYS)
> @@ -103,6 +125,8 @@ static void vidconsole_newline(struct udevice *dev)
>   	const int rows = CONFIG_CONSOLE_SCROLL_LINES;
>   	int i, ret;
>   
> +	draw_cursor(dev, false);
> +
>   	priv->xcur_frac = priv->xstart_frac;
>   	priv->ycur += priv->y_charsize;
>   
> @@ -342,6 +366,14 @@ static void vidconsole_escape_char(struct udevice *dev, char ch)
>   
>   		break;
>   	}
> +	case 'l':
> +		  draw_cursor(dev, false);
> +		  priv->cursor_visible = 0;
> +		  break;
> +	case 'h':
> +		  priv->cursor_visible = 1;
> +		  draw_cursor(dev, true);
> +		  break;
>   	case 'J': {
>   		int mode;
>   
> @@ -516,6 +548,11 @@ int vidconsole_put_char(struct udevice *dev, char ch)
>   	struct vidconsole_priv *priv = dev_get_uclass_priv(dev);
>   	int ret;
>   
> +	/*
> +	 * We don't need to clear the cursor since we are going to overwrite
> +	 * that character anyway.
> +	 */
> +
>   	if (priv->escape) {
>   		vidconsole_escape_char(dev, ch);
>   		return 0;
> @@ -530,6 +567,7 @@ int vidconsole_put_char(struct udevice *dev, char ch)
>   		/* beep */
>   		break;
>   	case '\r':
> +		draw_cursor(dev, false);
>   		priv->xcur_frac = priv->xstart_frac;
>   		break;
>   	case '\n':
> @@ -537,6 +575,7 @@ int vidconsole_put_char(struct udevice *dev, char ch)
>   		vidconsole_entry_start(dev);
>   		break;
>   	case '\t':	/* Tab (8 chars alignment) */
> +		draw_cursor(dev, false);
>   		priv->xcur_frac = ((priv->xcur_frac / priv->tab_width_frac)
>   				+ 1) * priv->tab_width_frac;
>   
> @@ -554,6 +593,8 @@ int vidconsole_put_char(struct udevice *dev, char ch)
>   		break;
>   	}
>   
> +	draw_cursor(dev, true);
> +
>   	return 0;
>   }
>   
> @@ -620,6 +661,7 @@ static int vidconsole_pre_probe(struct udevice *dev)
>   	struct video_priv *vid_priv = dev_get_uclass_priv(vid);
>   
>   	priv->xsize_frac = VID_TO_POS(vid_priv->xsize);
> +	priv->cursor_visible = false;
>   
>   	return 0;
>   }
> diff --git a/include/video_console.h b/include/video_console.h
> index 06b798ef10c..a908f1412e8 100644
> --- a/include/video_console.h
> +++ b/include/video_console.h
> @@ -83,6 +83,7 @@ struct vidconsole_priv {
>   	int escape_len;
>   	int row_saved;
>   	int col_saved;
> +	bool cursor_visible;
>   	char escape_buf[32];
>   };
>